Activeworkbook.name
is used to get the name of the active workbook from n different number of opened workbooks.
Thisworkbook.name
is used to get the name of the workbook in which the code is written or stored in the module of that workbook.
E.g if you are writing the code in the module or sheet of workbook A
then Thisworkbook.name
will return A
no matter which is the activeworkbook